1. Field of the Invention
The present invention relates to a reader coil antenna, and a non-contacting type card identification system using the same, and more particularly to an improved reader coil antenna which can form a magnetic field, transmit an operating frequency, and receive a frequency from a non-contacting type card in order to decode data of the non-contacting type card, and a non-contacting type card identification system using the same.
2. Description of the Related Art
Both a contacting type magnetic card having a magnetic strip portion which is rubbed for identification, and a non-contacting type card which transmits/receives data by frequency in a magnetic field space have been generally used as means for making payment. Examples of magnetic cards are credit cards and pre-paid telephone cards, while examples of the non-contacting type card are pre-paid transportation cards, and non-contacting type subway credit cards.
FIG. 1 is a block diagram illustrating a conventional non-contacting type card identification system. Referring to FIG. 1, the conventional non-contacting type card identification system 10 includes an antenna system 16, a card reader 18 and a control unit 20.
The card reader 18 generates a current to sense a non-contacting type card 14, and transmits a magnetic field formed by the current through the antenna system 16.
The non-contacting type card 14 manually charges a battery by the transmitted magnetic field, and transmits a signal including an internally-stored data to the antenna system 16.
The signal received in the antenna system 16 is output to the control unit 20 through the card reader 18.
The signal received in the control unit 20 is compared with master security information (not shown) stored in the control unit 20 to decide card identification, and is transmitted through the antenna system 16.
Further, the antenna system 16 includes a reader coil antenna, and generates the magnetic field by the applied current to the reader coil antenna and receives the signal from the non-contacting type card 14.
FIG. 2 is a perspective diagram illustrating a conventional reader coil antenna. As shown therein, the conventional reader coil antenna includes a driving loop antenna 22, double loop antennas 32, 34 and a non-magnetic conductive material 26.
Here, the double loop antennas 32, 34 are connected to each other in a cross-over type connection 36. In addition, the non-magnetic conductive material 26 contains aluminum, silver, copper, brass or gold to induce the magnetic field of the driving loop antenna 22 by providing a shield against an eddy current. A driving current for driving the non-contacting type card 14 is applied to terminals 28, 30 connected to the card reader 18. The magnetic field is generated in the driving loop antenna 22 due to the applied current. Here, an induced current is generated in the double loop antennas 32, 34 by the driving loop antenna 22. The induced current has a phase difference of 180xc2x0 from a direction of the current flowing through the driving loop antenna 22.
The double loop antennas 32, 34 are adhered to the surface of the non-magnetic conductive material 26. Accordingly, the magnetic field is generated on the front surface of the antenna system 16 where the non-contacting type card 14 is positioned, but induced and absorbed on the rear surface thereof.
In the above-described reader coil antenna, the driving loop antenna 22 and the double loop antennas 32, 34 have the opposite current direction. It is thus difficult to increase a reading distance which is the data recognition distance between the antenna system 16 and the non-contacting type card 14. Moreover, the non-magnetic conductive material 26 induces and absorbs the magnetic field, thus reducing strength of the magnetic field. As a result, the reading distance due to the magnetic field is further shortened.
Accordingly, an object of the present invention is to provide a reader coil antenna which can increase the reading distance, where a non-contacting type card is read, due to strength of an internal magnetic field, and a non-contacting type card identification system using the same.
In one aspect of the present invention, a reader coil antenna of a non-contacting type card identification system includes: an outer coil forming a predetermined loop, and forming a magnetic field by receiving a current; and at least one inner coil disposed inside the loop of the outer coil, for generating a constructive interference in a direction of the magnetic field of the outer coil by receiving a current.
In another aspect of the present invention, a non-contacting type card identification system using a reader coil antenna includes: the reader coil antenna for forming a magnetic field due to a signal applied to flow in an identical direction; a card reader for transmitting an operating signal through the reader coil antenna, and decoding an input signal from a non-contacting type card; and a control unit for deciding identification of the non-contacting type card according to the decoded signal.
According to the present invention, a sensing region of the center portion of the coil is increased due to the reader coil antenna provided with the identical direction current. In addition, strength of the magnetic field is increased near the center portion of the coil, by inserting a non-conductive magnetic material into the inner coil. As a result, the sensing region is increased, communication reliability is improved, and a dead zone is reduced.